Multi-Protocol Label Switching (MPLS) offers a significantly faster transmission by its concept of “route at the edge and switch in the core” and is widely adopted in many networks, including optical networks. As a datastream enters the edge of the network, the ingress Label Switch Router (LSR) reads the full address of the first data packet and attaches a small label in the packet header, which precedes the packet. A LSR at an intermediate node only needs to read this much abbreviated address in the small label so as to forward the packet to the next node. Accordingly, which is much faster than if the packets have to traverse to the application layer for examining the full IP address. In the MPLS network, the packets go through a shim layer at each intermediate node and are forwarded to the next node without traversing to the application layer of the nodes (as shown in FIG. 1(a)).
For restoration purposes, dual Label Switched Paths (LSPs) are established for a given connection, and one is identified as the primary LSP while the other as the secondary LSP. In the case where the primary LSP fails to deliver the message, possibly because it follows a failed path, the restoration mechanism operates to repeat the signaling message over the secondary path. On the secondary path, the intermediate nodes need to take action in support of establishing the restoration connection. Thus, contact needs to be made with their application layers directly through the use of a TCP/IP session so as to deliver instructions to the intermediate nodes. Conventionally, instead of traversing through the shim layer at nodes in the primary LSP, the message goes up the stack to the application layer at each intermediate node on the secondary LSP, being processed and reformatted there, and then goes down the stack to leave for the next node, such as shown in FIG. 1(b). Thus, a delay occurs due to the fact that the restoration message has to traverse the stack in both ways, and that the restoration message always has to wait for the processing at the application layer before being forwarded to the next node.
Therefore, there exists a need of the restoration management system in which the restoration message may be transmitted along the restoration path with less delay.